Electricity generated from Bacteria-Coated Rubber

Submitted by Bratislav Stankovic on Sat, 2014-02-15 12:21

A new kind of electric generator has a modest new unexpected energy source: A small strip of latex rubber coated with bacterial spores.

The contraption makes use of the harmless soil bacterium Bacillus subtilis, which has a neat survival trick. When nutrients are scarce, it turns itself into a tough little spore[1] that can withstand heat, desiccation, chemical assaults, radiation and anything else the world can throw at it.

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These spores respond to changes in humidity. When the air dries they shrivel up like grapes turning into raisins; when the air is moist they plump up again. Researchers from Harvard's Wyss Institute[3] and several other universities realized they could harness that physical movement, and could make an actuator to generate electricity.

In the experiment[4], published this week in Nature Nanotechnology, the researchers slathered one side of a sheet of rubber with the bacterial spores. When the sheet dried it curled up, much like a leaf does after it falls from a tree. Increasing the humidity caused the sheet to straighten out again.

Researcher Ozgur Sahin[5] then built a humidity driven generator out of Legos, in which the spore-coated rubber acts as a cantilever that flips back and forth, driving a rotating magnet to produce electricity.

According to the researchers, Such a device, properly scaled up, could use the natural evaporation of water to generate useful amounts of clean electricity.